This invention in general relates to automatic identification of a physical activity over a location, and specifically relates to a method and system for using information from independent sensor systems collaboratively in order to deduce or infer an accurate representation of a physical action or activity over a location, and to be able to use this information in order to provide appropriate reaction or feedback for management and control of the physical activity.
Radio Frequency Identification (RFID) is a set of technologies that uses the principle of electromagnetic signal transmission and communication, and allows uniquely identifiable elements (called tags) to be detected when the tags come within range of receivers (called readers). The tags may be attached to physical objects and the signal emitted from a RFID tag is used to identify the object associated with the tag. Currently, two different types of RFID systems exist: a passive RFID system that uses tags with an antenna and works on the principle of electromagnetic induction, and an active RFID system that uses a tag powered by an internal power source, for example, a battery.
Both technologies have unique capabilities and limitations that have thus far prevented their widespread adoption. Passive RFID tags work on the principle of electromagnetic induction. The simple construction of passive RFID tags allows these RFID tags to be produced very economically. However, the readers are necessarily much more complex in construction in order to broadcast signals strong enough to power the passive tags and yet sensitive enough to detect the weak return signal from the tag, therefore driving up the cost of passive readers. Also, since the signal strength for electromagnetic induction decays as the square of the distance between the tag and the reader, the read range is also very limited, for example to a maximum of few meters. Hence, passive RFID technology is currently suited only for tracking large quantities of items at very close ranges.
Active RFID tags are more complex, since active tags require an internal battery and an associated transmission circuitry, thereby making the active tags correspondingly much more expensive than a passive tag. However, an active reader is only a simple radio receiver and is fairly inexpensive to produce. As in the case of normal radio transmission, the range, even at extremely low power ranges normally used for active RFID transmission, is quite considerable, for example covering a few dozen meters or more. Hence, active RFID technology is ideal for tracking a limited number of items over a much larger area.
Additionally, current state of the art uses RFID technology as a means to detect the presence of a tagged object at a particular location or region. Using RFID technology in isolation seriously limits the amount of information available to a back-end information processing system—and reduces the usefulness of RFID technology. For instance, in the case of a security system, RFID sensors may detect the presence of authorized personnel at specified “control points” or locations, but the security system may be incapable of detecting unauthorized personnel who are not carrying RFID tags. So, relying on RFID sensor technology alone provides a very limited visibility of any physical activity or action.
Even when RFID technology works well, perhaps the significant limitation is that RFID provides only a limited view of any physical action or process. Any information system that uses inputs and produces an appropriate response requires a complete characterization of the physical process occurring within the system. For instance, a production planning system can perform effectively only when inputs such as production run quantities, stock and order levels, etc., are available to the production planning system. Therefore, the more complete the characterization of a physical process, the better is the quality of information processing and the corresponding deduced or inferred actions.
Any other physical characteristic, for example, weight, temperature, electric charge, pressure etc., may be sensed and used to form a more complete idea of the physical process. However, the challenge lies in integrating these different streams of information into a coherent characterization of the physical process that is occurring. And finally, along with sensing physical characteristics and forming an accurate representation of an actual physical process, there is a need for an appropriate feedback response for managing and controlling the physical process.
Thus, there is a need for a method and system that incorporates multi-sensor systems including RFID sensors and collates the information collected from the multi-sensor systems to provide a complete and accurate representation of an activity or object attribute, and provides a feedback response for managing and controlling the physical process.